Heat generating pouches of various configurations and shapes are designed and used for various purposes, such as hand warming, feet warming, and the like, by placing the heat generating pouch in a glove, mitten, shoe, etc. Heat generating pouches typically comprise a heat generating compound disposed between at least two layers of material, such as fabric, or the like, assembled to form a pouch. The heat generating compound emits heat during an exothermic chemical reaction resulting from exposure of the compound to air. Known heat generating compounds typically comprises a loose granular substance that is freely movable within the pouch. With a freely movable compound, when the pouch is placed flat, or horizontally, the compound is somewhat evenly distributed throughout the pouch. However, when the pouch is placed vertically, moved around, or jostled, the compound is drawn by gravity, shifts and settles toward one end of the pouch. This shifting and settling of the compound is sometimes referred to as a “tea-bag” effect. The tea-bag effect results in an uneven temperature profile along the surface area of the pouch. An uneven temperature profile can result in some areas not receiving heat, as desired, or an over concentration of heat in other areas.
The problem of the compound tending to shift and settle within the pouch has been addressed by other configurations of heat generating pouches. In one embodiment, the heat generating compound is contained within pucks or pellets that are disposed between at least two layers of material. The pucks or pellets comprise a heat generating compound capable of reacting with air in an exothermic reaction. The compound is compressed into concentrated, substantially rigid, pellets. In this configuration, however, the heat emission is concentrated at the pucks, resulting in an uneven heat distribution across the surface area of the pouch. Furthermore, because the pucks are rigid, the pucks do not conform to various contours of the human body against which the heat generating pouch may be placed.
The undesirable effect of a shifting compound has also been addressed by introducing air to the heat generating compound through only one of the two layers of material forming the pouch, while the other of the two layers of material comprises a self-adhesive. However, these adhesive pouches can not be easily inserted into pockets formed in socks, gloves, mittens, specially designed belts, or the like for use. Indeed, such adhesive pouches are typically fixed to an interior surface of a user's clothing. In this configuration of use, the pouch moves away from the user's skin as the clothing moves away from the user's skin. Furthermore, fixing the pouch to a user's clothing typically results in minimal or no pressure being applied to the pouch as the pouch is applied to the user's skin, thereby rendering the pouch less effective.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.